Polycarbonate is a type of engineering plastic that is in wide use in plastic industries.
Polycarbonate exhibits high resistance to heat since its glass transition temperature (Tg) may reach to about 150° C. due to a bulky molecular structure imparted thereto by, for example, bisphenol-A, and its carbonyl radicals of a carbonate group exhibit excellent rotary movement, thus providing ductility and rigidity to the polycarbonate. Furthermore, polycarbonate is an amorphous polymer having excellent transparency.
Not only that, polycarbonate has excellent impact resistance and compatibility with other resins, and thus is being used in a wide range of fields such as the electric⋅electronic field, optical instrument field, automobile field, construction field, medical field, food container field and other everyday life materials field and so forth.
Various kinds of inorganic fillers may be added to polycarbonate in order to improve the modulus and economic feasibility. Herein, examples of inorganic fillers that may be added include glass fiber, carbon fiber, carbon black and the like.
However, there is a problem that the polycarbonate matrix and the added inorganic filler have different refractive indexes, and the difference of refractive index of an interface between the matrix and the added inorganic filler affect transmittance and haze, resulting in a deterioration of transparency.
In order to resolve this problem, a polycarbonate copolymerized with polydimethylsiloxane (PDMS) has been used as a base resin together with the polycarbonate, but there still remains a problem of the transparency deteriorating significantly as the content of silicon in the polydimethylsiloxane increases.
Thus, there is still a need for a polycarbonate having excellent transparency while maintaining a good level of impact strength.